U.S. Pat. No. 4,351,077 to Hofmann illustrates one of numerous existing designs for automatic swimming pool cleaners. Cleaners such as that depicted in the Hofmann patent are configured for attachment, via a hose, to the inlet of an associated pump. They hence are commonly referred to as “suction-side” cleaners, as the inlet forms the “suction” side of the pump. When the pump operates, debris-laden water is drawn from the pool through the cleaner body (head) and hose to, typically, a filtration mechanism remote from the cleaner itself.
Many traditional suction-side cleaners include internal valves and external discs to effect movement of the cleaners within pools. As described in the Hoffman patent, for example, an internal flapper valve oscillates between two terminal positions within the fluid-flow path of the cleaner. The oscillation results, in use, to an intermittent cut-off flow through the head as the valve oscillates between its terminal positions and this in turn causes pulsations which result in longitudinal contractions and relaxations in the longitudinally resilient suction [hose] . . . . In consequence of these contractions and relaxations and a simultaneous reduction and increase of the force applied to hold the disc against the surface to be cleaned, a step by step movement of the head takes place over the surface to be cleaned.
See Hofmann, col. 3,11. 41-52 (numeral omitted).
Multiple discs have been designed to enhance cleaner performance in pools. U.S. Pat. No. 5,421,054 to Dawson, et al. and U.S. Pat. No. 5,418,995 to Rice, et al., illustrate annular discs having peripheral, upwardly-extending fins and generally circumferential slots, respectively. U.S. Pat. No. 4,530,125 to Hofmann details an annular disc with four equally-spaced, linear slits extending radially inward from the periphery toward the central aperture. U.S. Pat. No. 5,465,443 to Rice, et al. depicts yet other suction-side cleaner discs, including one having a series of generally radial, linear slits present solely in the rear section of the disc. This disc additionally accepts a cap similarly comprising rearwardly-positioned radial slits.
“Pressure-side” cleaners, by contrast, conventionally do not utilize annular discs to facilitate their movement within pools. These cleaners, which are connected (again typically via hoses) to outlets of associated pumps, instead use pressurized water flow to turn turbines, provide jet streams, or otherwise to effect their movement. One example of such a pressure-side cleaner in which a turbine drives wheels is shown in U.S. Pat. No. 3,936,899 to Henkin, et al.
Additionally unlike suction-side cleaners, pressure-side cleaners typically employ filtration mechanisms either within or proximate to their bodies. U.S. Pat. No. 5,930,856 to Van der Meyden, et al. illustrates a pressure-side cleaner with an internal screen-type filter for retaining debris, while the Henkin patent details such a cleaner with a filter in the form of a bag connected to the body. The Henkin patent further illustrates a float positioned externally of the body of the cleaner.
U.S. Pat. No. 5,802,653 to Roumagnac, finally, discloses a pressure-side cleaner incorporating a disc. The disc is indicated solely as being a “flange” or “flexible skirt,” however, without indication of its shape or structure. The Roumagnac patent additionally does not disclose including a float as part of a cleaning device, nor does it identify any stiffener or other support for its external debris receptacle.
Thus, although many versions of automatic pool cleaners have been designed, no cleaner currently includes a disc with generally radial non-linear slits. Likewise, no pressure-side cleaner incorporates a float into an interface between a filter bag and the body. Few stiffeners for bags presently exist, and, to applicants' knowledge, no current cleaner is adapted to sanitize water flowing through a filter bag attached to the cleaner. Nevertheless, the disclosure of each of the Hofmann '077 and '125 patents, the Dawson patent, the Rice '995 and '443 patents, the Henkin patent, the Van der Meyden patent, and the Roumagnac patent is hereby incorporated herein in its entirety by this reference.